1. Field of the Invention
This invention concerns an electric modular pruning and/or topping machine that can be used in agriculture, viticulture, fruit or tree growing or for brush clearing.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
More specifically, in the area of viticulture, machines of the trimmer, topper, pruner types are known of, that comprise cutter bars consisting of a row of blades with reciprocating movement, or of moving blades attached onto a belt or chain winding on two wheels spaced out and cutting the shoots whenever the teeth of a fixed counter-blade run by (see for example FR-2.239.191, FR-2.329.191, FR-2.019.417).
It is understood that these heavy, bulky and costly cutter bars cannot be standardized so as to fit all shapes of shrubs (vine stocks or others) to be pruned and/or topped, so that the manufacturers are led to propose a large variety of models, which causes investment and storage problems. In addition, the actuation of these cutter bars during operation requires significant power usage, and they become foul very fast, which impedes a clean cut.
Machines of the above-mentioned type are also known of (e.g., FR-2.423.142, FR-2.594.630, FR-2.787.966, FR-2.832.024), in which the horizontal and vertical cutting assemblies consist of rotary cutting tools, placed side-by-side or over-under, rotationally driven by hydraulic motors and pulleys and transmission belts.
In the above-mentioned FR-2.594.630 document, each cutting assembly consists of modules assembled one after the other, each module being made of a contoured modular casing that is attached, through an inserted box and a ball bearing, to a hollow shaft on which are mounted, on one side, a blade (5), and on the other side, a double pulley, the pulley of one of the modules being driven by a hydraulic motor, while the modules not directly motorized are driven through their double pulleys and belts.
The FR-2.832.024 document describes a trimmer cutter bar made of a plurality of over-under cutting modules mounted along a structural beam and comprising a double blade rotary knife. One of the modules is rotationally driven by an hydraulic motor that also drives a pulley so that the rotary movement is transmitted to the knife of the adjacent module that in turns transmits it to the cutting component of the next module (and so on if the cutter bar has more than three cutting modules), each time through a pulley and a transmission belt.
The cutting systems using rotary knives driven by hydraulic motors and transmission belts, whether based on a modular construction or not, have the following disadvantages:                difficult to achieve and maintain proper tension of the transmission belts so that the belts slip and overheat; tension adjustment of one of the belts often causes the tension of other belts to go out of adjustment;        obligation to align the rotational drive shafts of the knives so that the cutter bars can only be rectilinear;        necessity to have the transmission belts enclosed in a housing so as to eliminate the risks of getting caught in the vegetation, which impedes access to said belts, if needed;        risk of environmental pollution in case of oil leaks; and        difficult to provide high rotation speeds to the cutting tools although they are necessary to get clean cuts.        
Other major disadvantages of hydraulic modular cutting systems include:                complex assembly, including many hydraulic hoses lacking flexibility and cumbersome; and        significant weight making the cutter bar heavy.        
Multiple-row hydraulic toppers in particular require connection in series of the hydraulic motors. Such connection is limited as the differential pressures rapidly become inadequate to achieve the required cuts per motor. In addition, this series connection has the major disadvantage of pressure loading the shaft seals that thus become very fragile, which quickly causes leaks. To correct this disadvantage, it is necessary to add a drain hose so that the shaft seals are not pressurized.
Such mounting makes the assembly even more complex as the drain hoses must return directly to the hydraulic tank without any connector or coupler so as to prevent the slightest back-pressure.
Beyond 4 to 6 hydraulic motors mounted in series, the problems becomes such that no manufacturer tries larger mountings. It is therefore necessary for multi-row machines to use multiple flow dividers mounted one after the other, which causes oil wire-drawing that generated heat difficult to eliminate. The output of such an arrangement is very poor.
In addition, it should be pointed out that although machines with rotary knifes have been used for many years and offer the advantage of being able to work at fast forward speeds, this cutting system has the disadvantage of generating spatters and more specifically small leaf confetti that are harmful to the health of the vine and are very often carriers of cryptogamic diseases. These machines are also accused of being dangerous. However, European standards have been developed to protect the operator. The machines that give good results during the first topping in June on young shoots, work much less well as soon as the wood is lignified upon the second run, but mainly when topping before harvesting. On the hard wood, the vegetation is indeed shaken, which is harmful to the crop; the cuts are not clean and injuries to the wood are here also disease carriers.
The remedy to correct these disadvantages has been known for a long time since to prevent spatters and make clean cuts, it is necessary that, for example, the knives of approx. 34 cm diameter turn at high speeds above 3000 RPM. However, these high speeds cannot be easily achieved with hydraulic motors.
A pruning machine has already been proposed (U.S. Pat. No. 4,455,815) that comprises a cutter bar consisting of the juxtaposition of cutting devices, each containing a rotary cutter bar and a direct current electric motor for the individual rotational drive of this tool, all individual drive motors being supplied with direct current from a battery.
This device has serious disadvantages because of the use of direct current electric motors. The direct current supply indeed leads to using brush-type motors with a limited lifetime or motors without brushes, but using costly electronics. In addition, the rotation speed of those motors is not constant as it varies based on the torque. Finally, the cost price of these motors is generally high.
It has also been proposed (e.g., FR-2.412.436 and FR-2.850.328) to achieve the electric drive of agricultural tools from the power takeoff of an agricultural tractor, via a system transforming the mechanical energy into electric energy, this system comprising an electric generator, such as an alternator, a transmission permitting to connect the tractor power takeoff to the alternator rotor, this electric generator permitting to supply the electric drive motor of one or more agricultural machines. However, these are documents that describe a drive principle for machines, such as for example, grass mowers, but they do not address the applications of this principle to specific fields, and consequently not the solutions to problems that such applications may pose.